Crystallization inhibitor for paraffin wax in lubricating oils



" Patented Dec. 1, 1936 cnvsramza'rroiv INHIBITOR Fon mast"- rm wax IN mnnrcarma oms Garland n. B. Davis, Baton Rouge, 1a., assignor to Standard Oil Development Company, a corporation of Delaware No Drawing. Application April 21, 1932,

, Serial No. 606,765

16 Claims. (01. 8'l--9) T The presentinvention relate to improved lubricating oils and more specifically to high grade lubricating oils obtained from wax-containing stocks characterized by relatively low solidification or1congealing points. The invention will be fully understood from the following description of the newproducts and their method of manufacture.

In the production of high grade lubricating oils 10 it is known that low solidification or pour point is desirable and at the same time it. is recognized that wax-containing oils are highly desirable 'for lubricating quality. It is the present practice to remove wax from wax-containing .oils

5 by cold pressing or other low temperature means so as to produce parafiinic oilsof low cold test. These methods are expensive and undesirable since they materially reduce the yield and quality of oil.

In a prior U. S. Patent 1,815,022 of July 14,

1931, it is-disclosed that low pour oils canbe produced from high pour stocks by "the addition of certain pour inhibiting substances. The substances disclosed are of the class produced by the condensation of waxy hydrocarbons and aromatic hydrocarbons and have the peculiar prop-' ertyv of preventing or inhibiting solidification of waxy oils at their normal temperatures, and thus enable them to pour at considerably lower temperatures.

The present invention relates to a similar condensation product having similar properties but which is clearly distinguished from. the above product in that it is produced by condensation or polymerization of waxy hydrocarbons alone,

in absence of aromatics or other cyclic hydrocarbons. In the practice of the invention waxyhydrocarbons which may be parafiin wax,montan wax, ceresin or hydrocarbon oils rich in such sub- 40 stances, are first treated so as to convert the waxy material into an active derivative. capable of polymerization or condensation. For this purpose there are a variety of methods available of which the most desirable are those which do not substantially decompose the carbon structure of the wax; for example, the wax may be halogenated say by passing chlorine or bromine through the wax at a temperature of 200 to 300 F. This is preferably continued for 15 to 20 hours or more, so as toproduce. a derivative containing from about 10 .to 15% of chlorine. The chlorinated or brominated waxy hydrocarbons may be polymerized by the action of catalysts of the type of aluminum chloride at low temperatures. About 5 5 3 to 10%of the anhydrous aluminum chloride, or

its equivalents such as the other aluminum halides or boron fluoride and similar known sub-. stances, is used, based on the weight of the chlorinated wax, and the temperature is from about room temperature to 150 F., and prefera- 5 bly below 125' or even F. Low temperatures are made possible by the use of a highdegree of agitation and this results in more powerful inhibitors. The time of condensation is from about 2 to 20 hours, but there is an optimum time de- 10 pending on each set of conditions, and it is most desirable to withdraw samples at intervals to determine the best time by actual test. During this reaction copious volumes of hydrochloric, or

other halogen halide are evolved depending on 5 g the one used to halogenate the waxy hydrocarbon. -Catalytic sludge is then separated from the oil, preferably by reaction with water or alkali in the manner described in the co-pending application; Serial Number 576,208, filed November 19, 1931, or it may be settled by long standing, or otherwise. The ofl may then be treated in any convenient manner, for example, by washing with water, or alkali, or acid, orby clay filtration or the like, to produce a high grade refined product.

Residual chlorine is generally low but it may be substantially completely eliminated by'tre'ating the oil with metallic sodium'or mercury, or the like. I

In the prior description the paraflln orother 30 waxy hydrocarbon halides were used, but if desired partially dehydrogenated wax may be used and may be produced from the halide by gently heating to such a temperature as to cause the halogen-halide to split from the hydrocarbon. 35 This may be assisted by alkali, or metals such as zinc, or by catalytic' halides such as barium, or calcium chloride. The temperature varies somewhat with the method usedybut in general it is well below temperatures at which hydro- 40 carbons decompose and in this way it is, therefore, possible to obtain a partial dehydrogenation, that is to say, to the extent of preferably not more than '1 molecule of hydrogen for eachoriginal hydrocarbon molecule without breaking a the carbon to carbon linkages. Other methods for dehydrogenating the wax or waxy hydrocarbons may also be used, and especially those like. the one previously described, which do not decompose the carbon structure to 50 any substantial extent and, therefore, do not give rise to complicated side reactions resulting in tar formation, are applicable. I

If desired the olefin, or the.halide as the case maybe, my be concentrated before the polyu merization or condensation step by any known methods, for example, by sweating the oily halide from the solid wax, or by use of suitable solvents which may have chemical or purely physical action, but concentration is not required as the saturated wax does not interfere with the subsequent reaction. In fact, the wax or heavy viscous oil appears to be a valuable diluent and prevents agglomeration of the heavy condensed molecules during reaction.

When using dehydrogenated wax, or other active derivatives of waxy hydrocarbons in place of the halogenated wax as described above, the condensation is carried out in substantially the same manner and with substantially the same results. The proportion of thecatalytic material, temperatures and time are substantially the same.

As an example of the present process the following may be considered:

Paraffin wax meltingat about 122 F. is chlorinatedby bubbling chlorine through the wax at a temperature of about 300 F. This is continued for about 20 hours when the product shows a content of about 12.2% chlorine. paraffin is then charged to a still and 5% of dehydrated barium chloride is added. The temperature is slowly raised to" about 600 F. and

then raised quickly to about 750 F- During this time large volumes of hydrochloric acid gas are evolved but the carbonaceous material is otherwise substantially undecomposed. The material from the still is then transferred to an agitating vessel and an equal weight of paraflin wax is added, together with 5% by weight of anhydrous aluminum chloride based on the original chlorinated paraflin. Themixture is then thoroughly agitated and heated gently to a temperature of 125 and held at this point for about 12 hours. At the end of this time about two-thirds of its volume of kerosene is addedand the catalyst sludge is allowed to slowly settle. The supernatant liquid is withdrawn, washed with water and distilled to remove the kerosene and a large part of the wax. The oil obtained has the following characteristics:

Gravity 29.8.-A. P. I. Saybolt vis. at 100 F 300 seconds Saybolt vis. at 210 F 234 seconds Pour point F.

Flash point 620 F. Conradson carbon 1% When 1% of the above material is added to a natural motor oil obtained from Pennsylvania crude, and which has a natural pour point of 30 F. the pour point is reduced to 0 F. The inspection of the motor oil before and after the addition of 1% of the synthetic is as follows:

I With 1 percent (M81981 of synthetic Gravity 28.9 A. P. I; 28.7 A. P. I. Saybolt vis. at F 433 seconds 445 seconds. Saybolt vis. at 210 F 61 seconds. Flash 445 F, Pour 0 F.

perature is relatively fiat and the flash point is high in respect to viscosity. The oils are of good color, and are as stable to light, heat and oxidation as ordinary unblended oils, and do not in- Thechlor- I crease the tendency of oils containing the same to emulsify. They are characterized by substantially less residual carbon (Conradson carbon) than the oils produced by the method referred to previously, U. S. Patent 1,815,022, i. e; condensation of waxy hydrocarbons with aromatic hydro-' carbons, and appear to be substantially equal to them in respect to pour inhibiting strength. For pour reduction the synthetic oil is added in proportion generally less than 10% and in almost v every case less than 5%. The strength of the pour inhibitor may vary somewhat according to the conditions of its manufacture, and the exact quantity used to produce a particular reduction in pour depends on its strength, as well as the susceptibility of the 011. With distillate motor oils, spindle oils and the like it may be generally used in proportion of about 1% at which concentration there is a substantial pour reduction and only small or no substantial change in the ordinary physical properties. The oils for pour reducing purposes are almost always more viscous than the oils with which they are blended and a slight increase in viscosity may often be observed. The lighter fractions of the synthetic product do not appear to possess marked pour inhibiting strength and are often inactive. It is generally desirable to remove these fractions by reduction under vacuum maintainingthe temperature below the cracking point to segregate the polymers of high molecular weight forexample above 1000 or 1200.

In the above description the pour point of the oil is determined by the standard test method given in the report on Petroleum Products and Lubricants and Methods for Tests Relating to Petroleum Products by Committee D-2 of the' By these terms it is desired to include the reaction products obtained from the waxy hydrocarbon molecules through polymerization of any sort active derivatives thereof such as may be obtained by halogenation or partial dehydrogenation.

My invention is not to be limited by any theory of the condensation or polymerization reactions, nor to the precise steps or method of preparation,

but only by the following claims in which it is desired to claim all novelty inherent in the invention.

I claim: I

1. Product according to claim 12 in which the synthetic is used in proportion below about 10%, efiective substantially only for pour reduction.

2. Product according to claim 12 in which the synthetic is used in proportion below about 5%, eifective substantially only for pour reduction.

3. Product according to claim 12 in which the synthetic is used in proportion in the order of 1%. efl'e'ctlve substantially only 'for pour reduction.

4. Product according to claim 12 in which the synthetic is obtained by polymerization oi a waxy hydrocarbon containingfrom about 10 to 15% by weight of a halogen.

5. Product according to claim 12 in which the synthetic is obtained by polymerization of a partially dehydrogenated waxy hydrocarbon of the type produced by chlorination to 10 to 15% by weight of chlorine and then dechlorinating.

6. An improved lubricating oil of low cold test comprising a normally higher cold test oil blended with a. small quantity, in the order of 1%, of a high molecular weight hydrocarbon of the type produced by low temperature aluminum chloride polymerization of chlorinated paraflin in absence of cyclic materials. v v

'7. Product according to claim 6 in which the synthetic is of the type produced from paramn wax containing 10-15% of chlorine.

8. An improved lubricating oil of low cold test comprising a normally higher cold test oil blended with a small quantity in the order of 1% of a high molecular weight hydrocarbon of the type produced by low temperature aluminum chloride polymerization of a partially dehydrogenated paraflin wax of the type obtained by chlorination to 10 to 15% by weight of chlorine and then dedechlorinating in absence of cyclic material.

9. Product according to claim 8 in which the synthetic is of the type produced by polymerization of parafiin'wax dehydrogenated without decomposition of the carbon structure.

10. Product according to claim 12 in which the polymerization product is prepared at temperatures of the order of room temperature toabout 11. An improved lubricating oil of low cold test comprising a wax containing oil and a synthetic hydrocarbon formed by the polymeriza- 30 tion in absence of cyclic materials and at a temperature below that at which decomposition occurs, 01 an active derivative of a waxy hydrocarbon of the same carbon structure as the said waxy hydrocarbon, the synthetic being in pour reducing proportion.

12. An improved lubricating oil of low pour point comprising a wax -containing oil and a synthetic polymer or an uncracked waxy-hydrocarbon, prepared by condensation thereof in absence of cyclic materials at a temperature below the decomposing temperature of the wax, said polymer being in small amount whereby the pour point of the waxy oil is reduced.

' 13. An improved lubricating oil comprising a blend of a viscous hydrocarbon oil containing waxy constituents in proportion to give it a relatively high pour point, and a synthetic hydrocarbon prepared by polymerization in the absence of cyclic materials and at a temperature below that at which decomposition occurs, of an active derivative of a waxy hydrocarbon of the same carbon structure as the said waxy hydrocarbon, the synthetic being in pour reducing proportion.

14. Composition according to claim 13 in which the said synthetic has a molecular weight above 1000;

15. Composition according to claim 11 in which said active derivative is a halogenatedwax.

16. Composition according to claim 11 in which said active derivative comprises a mixture of olefines prepared by dehydrogenation of paraffine wax.

GARLAND H. B. DAVIS. 

